A broad integrated program for the study of the immunological response to malignant cells is proposed. Because of the intrinsic complications of the problem, it is separated with a series of narrower, definable questions based on simplified model systems. The major specific questions to be studied are: 1. Genetic regulation of the immunological response to self-antigens (Project 1). 2. Regulation of tumor growth by syngeneic antibody of different classes (Project 2A). 3. Effect of modification of lymphocyte membranes on lymphocyte reactivity (Project 2B). 4. Liposomes coated with antibodies specific for cell surface antigens to deliver chemotherapeutic agents (Project 3). 5. The isolation and characterization of tumor associated antigens form urine or other body fluids of human patients and experimental animals (Project 4).